Two-dimensional B$$_2$$C as a potential anode material for Mg-ion batteries with extremely high theoretical capacity

Abstract The development of new high-capacity anode materials using ions other than lithium as a charge carrier is one of the essential strategies in searching for next-generation high-performance rechargeable batteries. Herein, using first-principles computations, we explore a B $$_2$$ 2 C monolayer as a potential anode material for Mg-ion batteries. The high stability of the free-standing B $$_2$$ 2 C monolayer has been demonstrated via calculating the adsorption energy, phonon dispersion, and ab-initio molecular dynamics simulations. The metallic character of the B $$_2$$ 2 C monolayer, desirable from the point of view of energy storage, ensures good electronic conductivity during the battery charge/discharge process. The calculated migration energy barrier, open-circuit voltage, and theoretical specific capacity of the B $$_2$$ 2 C monolayer are much better than those of some other two-dimensional materials. These findings provide the B $$_2$$ 2 C monolayer as a potential candidate for Mg-ion battery anode material with a high theoretical specific capacity of 3187.55 mAh/g.